different approach to fixing "the other" aliasing issue

instead of copying the original value and constructing a Node
later, construct a Node immediately and copy it later.

Reviewed-by: thiago

1 files changed, 15 insertions, 37 deletions

diff --git a/src/corelib/tools/qlist.h b/src/corelib/tools/qlist.h
index e3b8e1b..67f63f3 100644
--- a/src/corelib/tools/qlist.h
+++ b/src/corelib/tools/qlist.h
@@ -98,25 +98,6 @@ struct Q_CORE_EXPORT QListData {
     inline void **end() const { return d->array + d->end; }
 };
 
-//////////////////////////////////////////////////////////////////////////////////
-//
-// QtPodForSize and QtPodForType are internal and may change or go away any time.
-// We mean it.
-//
-//////////////////////////////////////////////////////////////////////////////////
-template <int N> struct QtPodForSize {
-    // This base type is rather obviously broken and cannot be made
-    // working due to alignment constraints.
-    // This doesn't matter as far as QList is concerned, as we are
-    // using this type only for QTypeInfo<T>::isLarge == false.
-    typedef struct { } Type;
-};
-template <> struct QtPodForSize<1> { typedef quint8  Type; };
-template <> struct QtPodForSize<2> { typedef quint16 Type; };
-template <> struct QtPodForSize<4> { typedef quint32 Type; };
-template <> struct QtPodForSize<8> { typedef quint64 Type; };
-template <class T> struct QtPodForType : QtPodForSize<sizeof(T)> { };
-
 template <typename T>
 class QList
 {
@@ -529,16 +510,15 @@ Q_OUTOFLINE_TEMPLATE void QList<T>::append(const T &t)
                 QT_RETHROW;
             }
         } else {
-            typedef typename QtPodForType<T>::Type PodNode;
-            PodNode cpy = *reinterpret_cast<const PodNode *>(&t);
-            Node *n = reinterpret_cast<Node *>(p.append());
+            Node *n, copy;
+            node_construct(&copy, t); // t might be a reference to an object in the array
             QT_TRY {
-                void *ptr = &cpy;
-                node_construct(n, *reinterpret_cast<T *>(ptr));
+                n = reinterpret_cast<Node *>(p.append());;
             } QT_CATCH(...) {
-                --d->end;
+                node_destruct(&copy);
                 QT_RETHROW;
             }
+            *n = copy;
         }
     }
 }
@@ -564,16 +544,15 @@ inline void QList<T>::prepend(const T &t)
                 QT_RETHROW;
             }
         } else {
-            typedef typename QtPodForType<T>::Type PodNode;
-            PodNode cpy = *reinterpret_cast<const PodNode *>(&t);
-            Node *n = reinterpret_cast<Node *>(p.prepend());
+            Node *n, copy;
+            node_construct(&copy, t); // t might be a reference to an object in the array
             QT_TRY {
-                void *ptr = &cpy;
-                node_construct(n, *reinterpret_cast<T *>(ptr));
+                n = reinterpret_cast<Node *>(p.prepend());;
             } QT_CATCH(...) {
-                ++d->begin;
+                node_destruct(&copy);
                 QT_RETHROW;
             }
+            *n = copy;
         }
     }
 }
@@ -599,16 +578,15 @@ inline void QList<T>::insert(int i, const T &t)
                 QT_RETHROW;
             }
         } else {
-            typedef typename QtPodForType<T>::Type PodNode;
-            PodNode cpy = *reinterpret_cast<const PodNode *>(&t);
-            Node *n = reinterpret_cast<Node *>(p.insert(i));
+            Node *n, copy;
+            node_construct(&copy, t); // t might be a reference to an object in the array
             QT_TRY {
-                void *ptr = &cpy;
-                node_construct(n, *reinterpret_cast<T *>(ptr));
+                n = reinterpret_cast<Node *>(p.insert(i));;
             } QT_CATCH(...) {
-                p.remove(i);
+                node_destruct(&copy);
                 QT_RETHROW;
             }
+            *n = copy;
         }
     }
 }